JP2016088723A - Image formation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image formation device capable of suppressing bending of a sheet that is transported toward an upper side of a device body.SOLUTION: A laser printer 1 includes a device body 2 which contains an image formation part 7 and a first discharge tray 16, with a discharge unit 3 which contains a second discharge tray 61 capable of being attached to an upper part, a first wall 51, a flapper 53, and a second wall 52, and a curl application part 111 which applies curl on a sheet S so that the sheet S bends in a cross section of width direction. The curl application part 111 is configured to apply a curl on a sheet that is transported to an upper end part of the first wall 51.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an image forming apparatus in which a discharge unit can be attached to an apparatus main body.

  Conventionally, there has been known an image forming apparatus in which a discharge unit can be attached to an upper part of an apparatus main body (see Patent Document 1). The image forming apparatus is configured to convey the sheet toward the upper side of the apparatus main body when conveying the sheet to the discharge unit.

JP 2000-351511 A

  By the way, when the sheet is conveyed toward the upper side of the apparatus main body, the leading edge of the sheet is likely to be turned downward due to gravity, and the sheet may be bent during conveyance.

  The present invention has been made in view of the above background, and an object thereof is to provide an image forming apparatus in which a sheet conveyed toward the upper side of the apparatus main body is prevented from being bent.

In order to achieve the above object, an image forming apparatus according to the present invention has an image forming unit and a first discharge tray, and an apparatus main body to which a discharge unit having a second discharge tray can be attached, and the image forming unit. A first discharge unit that guides the sheet unloaded from the first discharge tray to the first discharge tray, and branches from the first discharge unit, and extends upward from a branch point between the first discharge unit and the sheet to the second discharge tray. And a curling portion for curling the sheet so that the sheet is curved in the cross section in the width direction.
The curling unit is configured to curl a sheet conveyed to the second discharge unit.

  When the sheet is discharged toward the second discharge unit, the sheet is conveyed toward the upper side of the apparatus main body through the second discharge unit. It is easy to bend. However, according to the configuration described above, the curling unit can curl the sheet conveyed to the second discharge unit so that the sheet is curved in the cross section in the width direction, whereby the stiffness of the conveyed sheet can be strengthened. Therefore, it is difficult for the leading edge of the sheet to face downward during conveyance of the second discharge unit, and the sheet can be prevented from being bent.

  In the configuration described above, the first discharge unit includes a first bending portion that curves away from the second discharge unit from the branch point toward the downstream side in the sheet conveyance direction. The curl amount of the sheet conveyed to the second discharge unit can be configured to be larger than the curl amount of the sheet conveyed to the first discharge unit.

  When a sheet is discharged to the first discharge tray, if the curl amount of the sheet is large, that is, if the stiffness of the sheet is strong, it becomes difficult to follow the first curved portion, so the leading end of the sheet hits the first curved portion and buckles. Cheap. However, according to the configuration described above, since the curl amount of the sheet conveyed to the first discharge unit is small, the sheet has a first curl amount compared to the configuration in which the first discharge unit and the second discharge unit have the same curl amount. It becomes easy to follow the first curved portion, and it is possible to suppress the leading end of the sheet from colliding with the first curved portion and buckling.

  The image forming apparatus described above includes the curling unit and a receiving unit that is disposed on the opposite side of the curling unit with the conveyed sheet interposed therebetween, and receives the conveyed sheet. The sheet conveyed by moving forward and backward to a first position that is a position that is disposed at a predetermined interval from the receiving portion and a second position that is closer to the receiving portion than the first position. When the curl amount adjusting mechanism capable of adjusting the curl amount is provided, the curl amount adjusting mechanism is disposed between the branch point of the first discharge unit and the second discharge unit and the image forming unit. It can be set as a structure.

  According to such a configuration, the curl amount of the conveyed sheet can be adjusted by moving the curling portion between the first position and the second position by the curl amount adjusting mechanism. Further, since the sheet can be curled before being conveyed to the second discharge unit, the sheet can be prevented from being bent before entering the second discharge unit.

  An image forming apparatus provided with the curl amount adjusting mechanism described above is movable between a first discharge position for guiding a sheet to the first discharge tray and a second discharge position for guiding a sheet to the second discharge tray. In the case of including a flapper, the curling unit moves forward and backward in conjunction with the flapper, and is disposed at the first position when the flapper moves to the first discharge position, and the flapper is at the second discharge position. It is good also as a structure arrange | positioned in the said 2nd position when it moves.

  According to such a configuration, the curling portion can be moved back and forth in conjunction with the flapper, so that the configuration can be simplified, the number of parts can be reduced, and the image forming apparatus can be downsized. .

  In the configuration provided with the curl amount adjusting mechanism described above, it is desirable that the curling portion be inclined so as to approach the receiving portion from the upstream side to the downstream side in the sheet conveying direction.

  According to such a configuration, since the sheet is conveyed following the inclination of the curling unit, the sheet is prevented from being caught by the curling unit, and the sheet can be easily conveyed.

  In the configuration including the curl amount adjusting mechanism, the discharge unit includes a third discharge unit that guides the sheet that has passed through the second discharge unit to the upper side, and a sheet branched from the third discharge unit. And a fourth discharge portion that guides to the two discharge trays. The fourth discharge portion moves from the branch point with the third discharge portion toward the downstream side from the upstream side in the sheet conveying direction. It can be set as the structure which curves so that it may leave | separate from the extended line of a part, and has a 2nd curved part with a larger curvature radius than the said 1st curved part.

  According to such a configuration, since the radius of curvature of the second curved portion is larger than that of the first curved portion, the curvature radius of the sheet is larger than that of the configuration in which the curvature radius of the first curved portion and the second curved portion is the same. It is possible to suppress the tip from buckling against the second bending portion.

  In the configuration including the curl amount adjusting mechanism described above, it is preferable that the first position is a position outside a path along which the sheet is conveyed.

  According to such a configuration, the sheet conveyed to the first discharge unit is not curled by the curling unit, so that the sheet is smoothly conveyed by the first discharge unit.

  When the image forming apparatus provided with the curl amount adjusting mechanism includes a control unit that controls the curl amount adjusting mechanism, the discharge unit guides the sheet that has passed through the second discharge unit to the third discharge. And a fourth discharge portion that branches from the third discharge portion and guides the sheet to the second discharge tray. The second discharge tray is arranged in a plurality in a direction in which the third discharge portion extends. When the sheet is discharged to each second discharge tray, the control unit is configured to determine the third discharge based on a curl amount of the sheet discharged to the second discharge tray disposed on the upstream side of the third discharge unit. The curl amount of the sheet discharged to the second discharge tray arranged on the downstream side of the section may be increased.

  The more downstream the sheet in the conveying direction, that is, the higher the sheet, the easier it is for the leading edge of the sheet to face down and the sheet to bend easily during the conveyance. Therefore, the sheet is not easily bent during conveyance.

  In the configuration including the control unit described above, the control unit may reduce the curl amount when the sheet is thicker than the predetermined thickness than when the sheet has the predetermined thickness.

  In the case of a sheet thicker than a predetermined thickness, the stiffness of the sheet is sufficiently strong. Therefore, when the sheet is conveyed upward, the leading end of the sheet is not easily bent, and the curling unit does not need to be curled more than necessary. On the other hand, if a thick curl is attached to a thick sheet, it becomes difficult for the user to correct the curl of the sheet because the sheet is difficult to return to its original shape while being deformed in a curled state. However, in the above-described configuration, the thick sheet that is difficult to bend is not curled more than necessary, so that the user can save the trouble of correcting the curl of the sheet while transporting the thick sheet satisfactorily.

  In the configuration including the above-described control unit, the control unit may be configured to increase the curl amount when the sheet is thinner than a predetermined thickness than when the sheet has the predetermined thickness.

  According to such a configuration, the curl amount of a sheet thinner than a predetermined thickness that is easy to bend can be increased, and the thin sheet can be hardly bent.

  In the configuration described above, the curling portion may be arranged in the second discharge portion.

  According to such a configuration, the sheet conveyed to the first discharge unit is not curled by the curling unit, so that the sheet is smoothly conveyed by the first discharge unit.

  In the configuration described above, the discharge unit includes a plurality of conveyance rollers arranged in the width direction of the sheet, and the plurality of conveyance rollers are arranged at positions different from a portion where the curl amount of the sheet is maximum. can do.

  According to the present invention, it is possible to prevent the sheet conveyed toward the upper side of the apparatus main body from being bent.

1 is a diagram illustrating a schematic configuration of a laser printer according to a first embodiment of the present invention. It is an enlarged view of the periphery of a curling part, Comprising: The figure (a) which shows when a curling part is a 1st position, and the figure (b) which shows when a curling part is a 2nd position. It is the figure which looked at the curl amount adjustment mechanism from the top, Comprising: The figure (a) which shows when the curling part is a 1st position, and the figure (b) which shows the time of a 2nd position. FIG. 4A is a diagram showing a gear mechanism when the curling portion is in the first position, and FIG. 4B is a diagram showing the gear mechanism when the curling portion is in the second position. It is a flowchart which shows operation | movement of a control part. It is a figure for demonstrating each path | route of a paper. It is a figure which shows the paper which passes the 2nd conveyance roller part. The figure (a) which shows when the curling part which concerns on 2nd Embodiment is a 1st tray position, the figure (b) which shows the time of the 2nd tray position, and the figure (c) which shows the time of the 3rd tray position FIG. 4D is a diagram (d) illustrating the fourth tray position. It is a flowchart which shows operation | movement of the control part which concerns on 2nd Embodiment. It is a flowchart which shows operation | movement of the control part which concerns on 3rd Embodiment. FIGS. 6A and 6B correspond to FIGS. 3A and 3B in the curl amount adjusting mechanism according to the fourth embodiment. FIGS. It is a figure equivalent to Drawing 7 concerning a 4th embodiment. It is an enlarged view of the curling part periphery which concerns on 5th Embodiment.

Next, an embodiment of the present invention will be described in detail with reference to the drawings as appropriate.
As shown in FIG. 1, a laser printer 1 as an example of an image forming apparatus of the present invention can be attached to an apparatus main body 2 that forms an image on a sheet S as an example of a sheet, and an upper part of the apparatus main body 2. The control unit 200 includes a discharge unit 3 that sorts and discharges the paper S conveyed from the main body 2 for each copy. In the following description, the direction will be described with reference to the user who uses the laser printer 1. That is, the right side in FIG. 1 is “rear”, the left side is “front”, the front side is “right”, and the back side is “left”. Also, the vertical direction in FIG.

  The apparatus main body 2 includes a supply unit 6 for supplying the paper S into the main body casing 5, an image forming unit 7, and a transport unit 8. The image forming unit 7 mainly includes an exposure device 20, a process unit 30 that forms a toner image on the paper S, and a fixing device 40 that thermally fixes the toner image transferred onto the paper S.

  The supply unit 6 is provided at a lower portion in the main body casing 5 and mainly includes a paper feed tray 11, a paper pressing plate 12, and a paper feed mechanism 13. The sheet pressing plate 12 is disposed on the bottom surface of the sheet feeding tray 11 and is pushed up by a push-up member 12A disposed below the sheet pressing plate 12, so that the front end portion can be rotated up and down around the rear end portion. Yes.

  The paper feed mechanism 13 has a pickup roller 13A and the like, and is configured to supply the paper S placed on the paper feed tray 11 to the process unit 30 one by one.

  The exposure apparatus 20 is disposed in the upper part of the main casing 5 and includes a laser light emitting unit (not shown), a polygon mirror, a lens, a reflecting mirror, and the like that are not shown. The exposure device 20 exposes the surface of the photosensitive drum 31 by scanning the surface of the photosensitive drum 31 with laser light based on the image data emitted from the laser light emitting unit.

  The process unit 30 is disposed below the exposure apparatus 20 and includes a drum unit 30A and a developing cartridge 30B.

  The drum unit 30 </ b> A mainly includes a photosensitive drum 31, a charger 32, and a transfer roller 33. Further, the developing cartridge 30 </ b> B is configured to be detachably attached to the main body casing 5 through an opening formed when the front cover 15 provided in the main body casing 5 is opened. The developing cartridge 30B mainly includes a developing roller 34, a supply roller (not shown), a layer thickness regulating blade, a toner storage unit that stores toner, and an agitator for stirring the toner in the toner storage unit.

  The process unit 30 uniformly charges the surface of the photosensitive drum 31 with a charger 32, and the exposure device 20 exposes the photosensitive drum 31 with laser light, whereby an electrostatic latent image based on image data is formed on the surface of the photosensitive drum 31. Is formed. Next, the toner in the developing cartridge 30 </ b> B is supplied to the electrostatic latent image on the photosensitive drum 31 by the rotating developing roller 34. As a result, a toner image is formed on the photosensitive drum 31. The toner image on the photosensitive drum 31 is transferred onto the paper S by applying a transfer bias between the photosensitive drum 31 and the transfer roller 33 while conveying the paper S between the photosensitive drum 31 and the transfer roller 33.

  The fixing device 40 is disposed behind the process unit 30 and mainly includes a heating roller 41 having a heating element and a pressure roller 42 that conveys the sheet S while being sandwiched between the heating roller 41. The fixing device 40 heat-fixes the toner image transferred onto the paper S while the paper S passes between the heating roller 41 and the pressure roller 42.

  The transport unit 8 has a discharge function for discharging the paper S on which the image is formed by the image forming unit 7 to the first discharge tray 16 or the discharge unit 3 formed on the upper surface of the main body casing 5. A re-conveying function for conveying the paper S on which the image is formed to the image forming unit 7 again is provided.

  The transport unit 8 includes a main transport path 81, a first discharge path 82, a second discharge path 83, and a re-transport path 84. The transport unit 8 is provided on a transport roller pair 54 provided on the main transport path 81, a pair of first discharge rollers 55 provided at the outlet of the first discharge path 82, and a re-transport path 84. And a plurality of re-conveying rollers 56.

  As shown in FIGS. 1 and 6, the main conveyance path 81 is a path for guiding the sheet S carried out from the fixing device 40 upward. The main conveyance path 81 is provided with a guide 50 that is disposed behind the fixing device 40 and guides the sheet S in a rearward and upward direction. The main conveyance path 81 forms a path from the nip position A1 between the heating roller 41 and the pressure roller 42 to a position A2 corresponding to the upper part of the downstream end of the guide 50.

  The first discharge path 82 is a path for guiding the sheet S on which the image is formed by the image forming unit 7 to the first discharge tray 16, and extends upward from the main transport path 81 and then gradually increases as it goes upward. It is curved in the forward direction. The first discharge path 82 constitutes a path from the position A2 to the nip position A3 of the pair of first discharge rollers 55.

  The first discharge path 82 is formed integrally with the rear cover 17 provided in the main casing 5 and is disposed on the front side of the first wall 51 extending in the vertical direction and the upper end portion 51A of the first wall 51, and extends in the front-rear direction. The second wall 52 and a flapper 53 having a substantially arc shape in cross section provided rotatably at the rear end of the second wall 52 serve as a guide for guiding the paper S to the first discharge tray 16. The inner peripheral surfaces of the first wall 51, the second wall 52, and the flapper 53 are an example of a first discharge unit.

  As shown in FIG. 2A, the first wall 51 includes an upper end portion 51A extending downward from the upper end of the main body casing 5, an inclined portion 51C extending rearward and downward from the lower end of the upper end portion 51A, and an inclined portion 51C. And a lower extension portion 51D extending downward from the lower end. The second wall 52 has a rear surface 52A that extends downward from the upper end of the main casing 5 and a lower surface 52B that extends substantially forward from the lower end of the rear surface 52A. The inclined portion 51 </ b> C of the first wall 51 and the lower surface 52 </ b> B of the second wall 52 constitute a part of a guide for guiding the paper S to the first discharge tray 16.

  As shown in FIG. 1, the flapper 53 rotates around the rear end of the second wall 52 to close the space between the first wall 51 and the second wall 52 and guide the first discharge path 82. The first discharge position (solid line position) that constitutes and the second discharge position (two-dot chain line position) that opens between the first wall 51 and the second wall 52 and closes the first discharge path 82 can be moved. It is configured. As shown in FIG. 2A, when the flapper 53 is in the first discharge position, the first discharge path 82 and the second discharge path in the first wall 51 are points that overlap the first wall 51 when viewed from the left-right direction. There are 83 branch points P.

  The inner peripheral surface of the flapper 53 forms a guide surface of the paper S at the first discharge position, and is an example of a first curved portion that gradually curves forward as it goes up from a position corresponding to the branch point P. The first curved surface 53A. That is, the first curved surface 53A is curved away from the first wall 51 from the branch point P toward the downstream side in the transport direction of the paper S.

  A curl amount adjusting mechanism 100 described later is provided below the flapper 53.

  As shown in FIG. 1, the first discharge roller 55 is configured to be rotatable in both the forward and reverse directions, and the sheet S is discharged to the first discharge tray 16 by rotating forward and the sheet S is rotated by rotating in reverse. It is designed to be pulled into the main body 2.

  The second discharge path 83 is a path that branches upward from the first discharge path 82 and guides the sheet S on which the image is formed by the image forming unit 7 to the discharge unit 3. As shown in FIG. 2B, the second discharge path 83 is formed between the upper end portion 51 </ b> A of the first wall 51 and the rear surface 52 </ b> A of the second wall 52. As shown in FIG. 6, the second discharge path 83 constitutes a path from the position A <b> 2 to a position A <b> 4 corresponding to the upper end of the main body casing 5. As shown in FIG. 2B, in the second discharge path 83, the upper end portion 51A of the first wall 51, that is, the portion extending upward from the branch point P serves as a guide for the paper S, and the upper end portion 51A. Is an example of a second discharge section.

  As shown in FIG. 1, the re-conveying path 84 is a path for guiding the sheet S on which an image is formed on one side by the reverse rotation of the first discharge roller 55 toward the image forming unit 7. The re-conveying path 84 is branched downward from a branch portion between the main conveying path 81 and the first discharge path 82, extends downward, curves forward, and extends under the image forming unit 7 forward. After that, it curves upward and extends toward the upstream side of the image forming unit 7.

  The discharge unit 3 branches from the third discharge path 85 connected to the second discharge path 83, the third discharge path 85, and a plurality of (four) fourth discharge paths 86 arranged vertically, and a plurality (4) arranged vertically. First discharge tray 61, a pair of second discharge rollers 65 provided corresponding to each second discharge tray 61, and a first transfer as an example of a transfer roller provided on the third discharge path 85. A roller 63 and a second transport roller 64 are provided.

  As shown in FIGS. 1 and 6, the third discharge path 85 is a path that guides the sheet S that has passed through the second discharge path 83 upward. In the third discharge path 85, a third wall 66 as an example of a third discharge portion provided on the rear side of the path and extending upward serves as a guide for guiding the sheet S upward. The third discharge path 85 forms a path from the position A4 to a position A51 of the third wall 66 that faces a position 66A that overlaps a second curved surface 67A (described later) when viewed in the left-right direction.

  The fourth discharge path 86 is a path that is provided corresponding to each second discharge tray 61 and guides the sheet S to each second discharge tray 61. In the fourth discharge path 86 corresponding to the uppermost first tray 61A among the plurality of second discharge trays 61, the sheet S is guided forward from the position 66A of the third wall 66 and guided to the first tray 61A. A fourth wall 67 as an example of the fourth discharge unit that serves as a guide for the paper S. Further, the uppermost fourth discharge path 86 forms a path from the position A51 to the nip position A61 of the uppermost second discharge roller 65.

  The fourth wall 67 has a second curved surface 67A as an example of a second curved portion that gradually curves forward from the position 66A of the third wall 66 toward the top. That is, the second curved surface 67A is curved away from the extension line of the third wall 66 from the branch point of the third wall 66 toward the downstream side in the transport direction of the paper S. The second curved surface 67A has a larger radius of curvature than the first curved surface 53A.

  Also, as shown in FIG. 1, among the plurality of second discharge trays 61, the fourth corresponding to the second second tray 61 </ b> B, the third third tray 61 </ b> C and the lowermost fourth tray 61 </ b> D from the top. The discharge path 86 is provided with a swing member 62 having a substantially circular arc in a sectional view.

  The swing member 62 is disposed at a branch portion of the third discharge path 85 and the fourth discharge path 86, and is an open position where the fourth discharge path 86 is opened (position of the swing member 62 corresponding to the third tray 61C in the drawing). And a closing position for closing the fourth discharge path 86 (the position of the swinging member 62 corresponding to the second tray 61B and the fourth tray 61D shown in the figure). Accordingly, the swing member 62 corresponding to the second discharge tray 61 from which the paper S is discharged is set to the open position, and the swing member 62 corresponding to the second discharge tray 61 from which the paper S is not discharged is set to the closed position. The sheet S can be discharged to each second discharge tray 61 appropriately selected by the user.

  Further, as shown in FIG. 6, the fourth discharge path 86 corresponding to the second tray 61B is from a position A52 branched from the third discharge path 85 to a nip position A62 of the second discharge roller 65 second from the top. The fourth discharge path 86 corresponding to the third tray 61C is a path from the position A53 branched from the third discharge path 85 to the third nip position A63 of the second discharge roller 65 from the top. It is composed. The fourth discharge path 86 corresponding to the fourth tray 61D constitutes a path from a position A54 branched from the third discharge path 85 to a nip position A64 of the lowermost second discharge roller 65.

  As shown in FIG. 1, the swinging member 62 is a guide that branches from the third wall 66 and guides the paper S to the corresponding second discharge tray 61 when in the open position. It is an example. More specifically, in the fourth discharge path 86 corresponding to the second tray 61B, the inner peripheral surface of the uppermost swing member 62 at the open position serves as a guide for guiding the paper S to the second tray 61B. In the fourth discharge path 86 corresponding to the third tray 61C, the inner peripheral surface of the second swinging member 62 from the top at the open position serves as a guide for guiding the paper S to the third tray 61C. Yes. In the fourth discharge path 86 corresponding to the fourth tray 61D, the inner peripheral surface of the lowermost swinging member 62 at the open position serves as a guide for guiding the paper S to the fourth tray 61D. .

  Further, the inner peripheral surface of the swinging member 62 is a third curved surface as an example of a second curved portion that gradually curves in the forward direction as it goes upward, like the second curved surface 67A, in the open position. 62A. In FIG. 1, the third curved surface 62A of the swinging member 62 corresponding to the third tray 61C is shown as an example of the second curved portion. However, when the first tray 61A is selected, all the curved surfaces 62A are selected. The swing member 62 is in the closed position, and the second curved surface 67A is an example of the second curved portion. When either the second tray 61B or the fourth tray 61D is selected, only the swing member 62 corresponding to the selected tray is in the open position, and the third curved surface 62A of the swing member 62 is selected. Is an example of the second bending portion.

Next, the curl adjustment mechanism 100 will be described.
As shown in FIG. 2A, the curl adjustment mechanism 100 is a mechanism for adjusting the curl amount of the paper S, and is disposed between the branch point P and the image forming unit 7 (see FIG. 1). ing. Specifically, the curl amount adjusting mechanism 100 is disposed downstream of the fixing device 40 and upstream of the branch point P. The curl amount adjusting mechanism 100 includes a main body casing 5 that includes an advance / retreat member 110 that is supported so as to be movable in the front-rear direction, and a receiving portion 120 that is disposed on the opposite side of the advance / retreat member 110 with the sheet S being conveyed therebetween. ing.

  3A and 4A, the advance / retreat member 110 includes a curling portion 111 extending in the front-rear direction, an extending portion 112 extending to the left from the rear end of the curling portion 111, and an extension. A rack gear 113 extending forward from the left end of the portion 112.

  As shown in FIGS. 3A and 3B, the curling unit 111 is configured to be able to curl the sheet S so that the sheet S is curved in the cross section in the width direction. It is arrange | positioned in the position facing the center of the left-right direction. The curling portion 111 is configured to be able to advance and retreat with respect to the first wall 51 through a hole 51B penetrating the first wall 51 in the front-rear direction.

  The curling unit 111 has a first position (a position shown in FIG. 3A) arranged at a predetermined interval from the receiving part 120 and a second position (a position closer to the receiving part 120 than the first position). 3 (b)). Here, the first position is a path along which the sheet S is conveyed, that is, a position outside the first discharge path 82, and the second position is the front end 111 </ b> A of the curling unit 111 in the first discharge path 82. It is a position where the front end 111A can come into contact with the paper S as well as the position where it has entered.

  As shown in FIGS. 2A and 2B, the front end 111A of the curling portion 111 is inclined so as to extend obliquely upward. That is, the front end 111 </ b> A of the curling unit 111 is inclined so as to approach the receiving unit 120 from the upstream side toward the downstream side in the transport direction of the paper S.

  The lower end of the front end 111 </ b> A of the curling portion 111 is located behind the front end of the first wall 51 in the second position. Note that the lower end of the front end 111A of the curling portion 111 may be the same position in the front-rear direction as the front end of the first wall 51 when in the second position.

  As shown in FIGS. 3A and 3B, the extending portion 112 passes through the rear side of the first wall 51 and extends to a position on the left side from a side wall (not shown) on which the flapper 53 is supported. As shown in FIGS. 4A and 4B, the rack gear 113 is configured such that a driving force is input from a gear mechanism 114 provided on the side wall.

  The gear mechanism 114 includes a flapper gear 114A fixed to the left end of the flapper 53, a first gear 114B that meshes with the flapper gear 114A, and a second gear 114C that meshes with the first gear 114B and the rack gear 113. By this gear mechanism 114, the curling portion 111 is disposed at the first position when the flapper 53 is disposed at the first discharge position (see FIG. 4A), and the flapper 53 is disposed at the second discharge position. At the second position (see FIG. 4B). That is, the curling portion 111 can advance and retreat in conjunction with the flapper 53.

  As shown in FIG. 3B, the receiving unit 120 is configured to receive the conveyed paper S when the curling unit 111 is in the second position, and includes a plurality of ribs 121 arranged side by side. It is configured. The plurality of ribs 121 have a smaller amount of protrusion toward the rear side as the ribs 121 arranged on the inner side in the left-right direction, and the amount of protrusion at the center portion in the left-right direction facing the curling portion 111 is the smallest. . In other words, the plurality of ribs 121 are configured such that each rear surface 121A is arranged on an arc that protrudes forward.

  Therefore, when the curling unit 111 is disposed at the second position, the sheet S to be transported is pushed frontward by the front end 111A of the curling unit 111 in the width direction and the entire portion is formed by the plurality of ribs 121. Since it follows the rear surface 121A, curling is performed so that the cross section in the width direction of the paper S is curved forward.

  In other words, the curl amount of the sheet S conveyed to the second discharge path 83 is larger than the curl amount of the sheet S conveyed to the first discharge path 82. The curl amount here refers to a distance D in the front-rear direction between a line L connecting one end to the other end in the width direction and the bottom of the curved portion of the sheet S in the width direction cross section of the sheet S.

  In addition, as shown in FIG. 7, a plurality of first conveyance rollers 63 and second conveyance rollers 64 (only the second conveyance rollers 64 are illustrated) are arranged side by side in the width direction of the paper S. The first conveyance roller 63 and the second conveyance roller 64 are arranged at positions different from the portion where the curl amount of the sheet S is maximized. This suppresses the curling of the paper S attached by the curling unit 111 from being canceled by the first transport roller 63 and the second transport roller 64.

Next, the control unit 200 will be described.
As shown in FIG. 1, the control unit 200 includes, for example, a CPU, a ROM, a RAM, and the like, and controls the curl amount adjusting mechanism 100 by performing arithmetic processing based on a program prepared in advance. Is configured to run.

  The control unit 200 executes switching control for disposing the flapper 53 at one of the first discharge position and the second discharge position. Specifically, when the first discharge tray 16 is selected, the control unit 200 sets the flapper 53 to the first discharge position. As a result, the curling portion 111 is arranged at the first position in conjunction with the flapper 53. Then, when any of the second discharge trays 61 is selected, the control unit 200 sets the flapper 53 to the second discharge position. As a result, the curling portion 111 is arranged at the second position in conjunction with the flapper 53. Note that the selection of the discharge tray of the paper S can be appropriately selected by the user when the print job is transmitted.

  When any one of the second discharge trays 61 is selected, the control unit 200 executes control to place each swinging member 62 at either the open position or the closed position. Specifically, when the first tray 61A is selected, the control unit 200 sets each swing member 62 at the closed position. As a result, the fourth discharge path 86 other than the fourth discharge path 86 corresponding to the first tray 61A is blocked, and the sheet S is discharged to the first tray 61A through the fourth discharge path 86 corresponding to the first tray 61A. Is done.

  In addition, when any of the trays 61B, 61C, 61D other than the first tray 61A is selected, the control unit 200 sets the swing member 62 corresponding to the selected tray to the open position, and swings other than that. The moving member 62 is set to the closed position. As a result, only the fourth discharge path 86 corresponding to the selected tray is opened, and the paper S is discharged to the tray through the fourth discharge path 86 corresponding to the selected tray.

  The control unit 200 configured as described above executes control according to the flowchart shown in FIG. In this control, the description of the control flow of the swing member 62 is omitted.

  As shown in FIG. 5, the control unit 200 determines whether there is a print job (S1). In step S1, if the control unit 200 determines that there is no print job (S1: No), the control unit 200 ends this control. If it is determined that there is a print job (S1: Yes), the first discharge is performed. It is determined whether or not the tray 16 has been selected (S2).

  When the first discharge tray 16 is selected in step S2 (S2: Yes), the control unit 200 sets the position of the flapper 53 to the first discharge position (S3). Thereby, the position of the curling unit 111 is set to the first position.

  When the second discharge tray 61 is selected in step S2 (S2: No), the control unit 200 sets the position of the flapper 53 to the second discharge position (S4). Thereby, the position of the curling unit 111 is set to the second position.

  After steps S3 and S4, the control unit 200 executes print control (S5) and ends this control.

The operational effects of the laser printer 1 configured as described above will be described.
As shown in FIG. 2A, when the paper S is discharged to the first discharge tray 16, the flapper 53 is disposed at the first discharge position, and the curling portion 111 is disposed at the first position. Here, if the cross section in the width direction of the paper S is curled, it becomes difficult to follow the first curved surface 53A having a small radius of curvature, so that the leading edge of the paper S tends to buckle against the first curved surface 53A.

  However, in the present embodiment, since the curling portion 111 is in the first position, that is, the position outside the first discharge path 82, the sheet S is not curled with a curved cross section in the width direction, and the first curved surface 53A. Are smoothly transported following the above and discharged to the first discharge tray 16.

  On the other hand, as shown in FIG. 2B, when the paper S is discharged to the second discharge tray 61, the flapper 53 is disposed at the second discharge position, and the curling portion 111 is disposed at the second position. As a result, the sheet S is conveyed toward the second discharge path 83, that is, upward, while being gradually curled by the inclination of the front end 111A of the curling unit 111 (see FIG. 3B).

  Thus, the curling of the cross section in the width direction of the paper S makes it difficult for the front end of the paper S to face downward while the paper S is transported in the second discharge path 83, and the paper S is prevented from being bent. The Therefore, the sheet S can smoothly go up, that is, toward the third discharge path 85.

  As shown in FIG. 1, after passing through the second discharge path 83, the sheet S is transported along the third discharge path 85 in the discharge unit 3 and transported along the third curved surface 62A. Here, since the third curved surface 62A has a larger radius of curvature than the first curved surface 53A, the leading edge of the sheet S is the third curved surface compared to the configuration in which the third curved surface has the same curvature radius as the first curved surface. The buckling against the curved surface 62A is suppressed. Then, the sheet S is smoothly conveyed through the fourth discharge path 86 and discharged to the second discharge tray 61.

According to the above, the following effects can be obtained in the present embodiment.
The curling unit 111 can curl the sheet S conveyed in the second discharge path 83 so that the cross section in the width direction is curved, so that the stiffness of the conveyed sheet S can be increased. During the conveyance of the path 83 and the third discharge path 85, the leading edge of the sheet S is difficult to face downward, and the sheet S can be prevented from being bent. Further, since the stiffness of the paper S is strong, for example, even if the number of transport rollers in the second discharge path 83 and the third discharge path 85 is small, the paper S can be smoothly transported upward. .

  Since the sheet S conveyed to the first discharge path 82 is not curled with a curved cross section in the width direction, the sheet S has a curvature as compared with the configuration in which the same curl is applied to the first discharge path and the second discharge path. It becomes easy to follow the first curved surface 53A with a small radius, and the leading edge of the paper S can be prevented from buckling against the first curved surface 53A.

  By the way, in order to reduce the size of the apparatus main body 2, when the height in the vertical direction is reduced, it is desirable to design the radius of curvature of the first curved surface 53A in the first discharge path 82 to be small. On the other hand, since the discharge unit 3 is attached to the apparatus main body 2 as necessary, the height in the vertical direction does not have to be reduced more than necessary. Therefore, the radius of curvature of the second curved surface 67A and the third curved surface 62A in the fourth discharge path 86 can be designed to be larger than that of the first curved surface 53A.

  The curl amount adjusting mechanism 100 can move the curling unit 111 between the first position and the second position, so that the curl amount of the conveyed paper S can be adjusted. Further, since the curl amount adjusting mechanism 100 is disposed between the flapper 53 and the image forming unit 7, the paper S can be curled before being conveyed to the second discharge path 83. Therefore, the sheet S can be prevented from being bent before entering the second discharge path 83.

  Since the flapper 53 and the curling unit 111 are interlocked, the curling unit 111 can be advanced and retracted by switching the position of the flapper 53. Therefore, a simple configuration can be achieved, the number of parts can be reduced, and the laser printer 1 can be downsized.

  Since the paper S is transported following the inclination of the curling unit 111, the paper S is prevented from being caught by the curling unit 111, and the paper S can be easily transported.

  Since the radius of curvature of the second curved surface 67A and the third curved surface 62A is larger than that of the first curved surface 53A, the radius of curvature of the second curved surface and the third curved surface is compared with the same configuration as that of the first curved surface. Thus, it is possible to suppress the leading edge of the paper S from buckling against the second curved surface 67A and the third curved surface 62A.

  When the paper S is transported through the first discharge path 82, curling such that the cross section in the width direction of the paper S is not curled is provided, so that the transport of the paper S on the first curved surface 53A becomes smooth.

  Next, a second embodiment of the present invention will be described. In the present embodiment, the same components as those in the previous embodiment are denoted by the same reference numerals, and the description thereof is omitted. In the present embodiment, the curling portion 111 is configured not to be interlocked with the flapper 53. That is, in the present embodiment, the curling unit 111 and the flapper 53 are driven by separate driving sources.

  When discharging the paper S to each second discharge tray 61, the control unit 200 executes curl amount change control for changing the curl amount of the paper S depending on the position of the second discharge tray 61. Specifically, the control unit 200 executes control to increase the curl amount of the paper S, that is, the advance amount of the curling unit 111 in order from the upstream side in the transport direction of the paper S in the third discharge path 85.

  More specifically, when discharging the paper S to the uppermost first tray 61A, the control unit 200 sets the curling unit 111 to the first tray position (see FIG. 8A), and the second from the top. When the sheet S is discharged to the second tray 61B, the curling unit 111 is set at a second tray position that is farther from the receiving unit 120 than the first tray position (see FIG. 8B). As a result, the curl amount C1 of the sheet S conveyed toward the first tray 61A is larger than the curl amount C2 of the sheet S conveyed toward the second tray 61B.

  Then, when discharging the paper S to the third tray 61C that is third from the top, the control unit 200 sets the curling unit 111 to a third tray position that is farther from the receiving unit 120 than the second tray position ( (Refer FIG.8 (c)). As a result, the curl amount C2 of the paper S conveyed toward the second tray 61B becomes larger than the curl amount C3 of the paper S conveyed toward the third tray 61C.

  Furthermore, when discharging the paper S to the lowermost fourth tray 61D, the control unit 200 sets the curling unit 111 to a fourth tray position that is further away from the receiving unit 120 than the third tray position (FIG. 8 (d)). As a result, the curl amount C3 of the paper S conveyed toward the third tray 61C becomes larger than the curl amount C4 of the paper S conveyed toward the fourth tray 61D.

  By controlling in this way, the curl amount of the paper S discharged to the second discharge tray 61 disposed on the upstream side of the third discharge path 85 is set to the second disposed on the downstream side of the third discharge path 85. The curl amount of the paper S discharged to the discharge tray 61 is increased.

  The control unit 200 configured as described above executes control according to the flowchart shown in FIG.

  As shown in FIG. 9, the processes from step S1 to steps S3 and S4 are the same as those in FIG. After step S3, the control unit 200 sets the curling unit 111 to the first position (S31).

  After step S4, the control unit 200 determines whether or not the first tray 61A has been selected (S41). When the first tray 61A is selected (S41: Yes), the control unit 200 sets the curling unit 111 to the first tray position (S42).

  When the first tray 61A is not selected (S41: No), the control unit 200 determines whether or not the second tray 61B is selected (S43). When the second tray 61B is selected (S43: Yes), the control unit 200 sets the curling unit 111 to the second tray position (S44).

  When the second tray 61B is not selected (S43: No), the control unit 200 determines whether or not the third tray 61C is selected (S45). When the third tray 61C is selected (S45: Yes), the control unit 200 sets the curling unit 111 to the third tray position (S46). When the third tray 61C is not selected (S45: No), that is, when the fourth tray 61D is selected, the control unit 200 sets the curling unit 111 to the fourth tray position (S47).

  After steps S31, S42, S44, S46, and S47, the control unit 200 executes print control (S5) and ends this control.

The effects of the laser printer 1 according to the second embodiment configured as described above will be described.
When the sheet S is conveyed to the second discharge path 83, the sheet S is discharged to any one of the plurality of second discharge trays 61. Here, in order to reduce the number of parts, in the configuration in which the first transport roller 63 and the second transport roller 64 in the third discharge path 85 are not provided, the sheet S is being transported as it goes to the upper side of the third discharge path 85. Tends to face downward, and the sheet S is easily bent. However, in the present embodiment, the curl amount of the paper S increases toward the downstream side in the transport direction, so that the paper S can be prevented from being bent during the transport of the third discharge path 85.

  Next, a third embodiment of the present invention will be described. Note that the third embodiment has substantially the same configuration as that of the second embodiment, and the control unit 200 controls the curl amount of the paper S according to the position of the second discharge tray 61 of the second embodiment. Instead of this, a control for changing the curl amount of the paper S depending on the thickness of the paper S can be executed.

  Specifically, when the sheet S is larger than a predetermined thickness, the control unit 200 sets the curling unit 111 to a small curl position (for example, the position shown in FIG. 8D). When the sheet S has a predetermined thickness, the control unit 200 sets the curling unit 111 to a middle curl position (for example, the position of FIG. 8B) that is closer to the receiving unit 120 than the small curl position. Then, when the sheet S is smaller than the predetermined thickness, the control unit 200 sets the curling unit 111 to a large curl position (for example, the position of FIG. 8A) closer to the receiving unit 120 than the middle curl position. .

  By controlling in this way, the curl amount is smaller in the case of the paper S thicker than the predetermined thickness, and the predetermined thickness in the case of the paper S thinner than the predetermined thickness. The curl amount is larger than that of the paper S.

The control unit 200 configured as described above executes control according to the flowchart shown in FIG.
As shown in FIG. 10, the processes from step S1 to steps S31 and S4 are the same as those in FIG. After step S4, the control unit 200 determines whether or not the sheet S is larger than a predetermined thickness (step S141).

  If it is determined in step S141 that the sheet S is larger than the predetermined thickness (S141: Yes), the control unit 200 sets the curling unit 111 to the small curl position (S142). When it is determined that the sheet S is smaller than the predetermined thickness (S141: No), the control unit 200 determines whether or not the sheet S has a predetermined thickness (S143).

  When it is determined in step S143 that the sheet S has a predetermined thickness (S143: Yes), the control unit 200 sets the curling unit 111 to the middle curl position (S144). When it is determined that the sheet S is smaller than the predetermined thickness (S143: No), the control unit 200 sets the curling unit 111 to the large curl position (S145). After steps S142, S144, and S145, the control unit 200 executes print control (S5) and ends this control.

  By the way, in the case of the paper S thicker than the predetermined thickness, the stiffness of the paper S is sufficiently strong. There is no. On the other hand, if the thick paper S has a large curl, it becomes difficult for the user to correct the curl of the paper S because the paper S is difficult to return to its original shape while being deformed.

  However, in this embodiment, the thick paper S that is difficult to bend is not curled more than necessary, so that the user can save the trouble of correcting the curl of the paper S while transporting the thick paper S satisfactorily. In addition, the curl amount of the sheet S that is easier to bend than the sheet S having a predetermined thickness and that is thinner than the predetermined thickness can be increased so that the thin sheet S is not easily bent.

  Next, a fourth embodiment will be described. In the fourth embodiment, as shown in FIGS. 11A and 11B, a plurality of curling portions 211 are provided side by side in the left-right direction.

  Each curling portion 211 is provided at a position shifted from each rib 121 in the left-right direction. The plurality of ribs 121 have the same protruding amount. A plurality of holes 51 </ b> B in the first wall 51 are formed corresponding to the curling portions 211.

  As shown in FIG. 12, the first conveyance roller 63 and the second conveyance roller 64 (only the second conveyance roller 64 is illustrated) are positions different from the portion where the sheet S is curled by the curling unit 211. The ribs 121 are disposed at positions corresponding to the portions where the ribs 121 are provided (only four pairs are shown in FIG. 12). Other configurations are the same as those in the first embodiment.

  According to such a configuration, as shown in FIG. 11B, when the curling portion 211 is advanced toward the receiving portion 120, the sheet S is moved toward the receiving portion 120 by the tip of each curling portion 211. Pressed. A portion of the paper S that is not pressed by the curling portion 211 is received by each rib 121. Therefore, a plurality of curls can be attached to the paper S, the leading edge of the paper S is less likely to face downward, and the paper S can be prevented from being bent.

  Next, a fifth embodiment will be described. In the fifth embodiment, as shown in FIG. 13, the curling portion 111 is disposed above the flapper 53.

  Specifically, the curling portion 111 is provided so as to protrude from the upper end portion 51 </ b> A of the first wall 51 into the second discharge path 83, and does not advance or retreat with respect to the first wall 51. . Other configurations are the same as those in the first embodiment.

  Even in such a configuration, the curling unit 111 does not curl the sheet S conveyed to the first discharge path 82, so that the conveyance of the sheet S in the first discharge path 82 becomes smooth. Further, since curling is performed only on the sheet S conveyed to the second discharge path 83, it is not necessary to advance or retract the curling unit 111. Therefore, it is not necessary to provide the curl amount adjusting mechanism 100 as in each of the above embodiments, the number of parts can be reduced, and a simple configuration can be achieved.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment. About a concrete structure, it can change suitably in the range which does not deviate from the meaning of this invention.

  In the above-described embodiment, the front end 111A of the curling portion 111 is inclined, but the present invention is not limited to this and may not be inclined.

  In the said embodiment, although the 1st conveyance roller 63 and the 2nd conveyance roller 64 were provided in the discharge unit 3, this invention is not limited to this. For example, in a laser printer that transports only a sheet S having a relatively long length in the transport direction, such as A4 size paper, the front end of the sheet S is moved to the position of the transport roller pair 54 until the rear end of the sheet S reaches each position. In the case of a configuration capable of reaching the position of the two discharge rollers 65, the first transport roller and the second transport roller may not be provided. Even with such a configuration, the paper S is strengthened by being curled by the curling unit 111, so that the paper S can be smoothly conveyed upward.

  In the above embodiment, the present invention is applied to the laser printer 1. However, the present invention is not limited to this, and the present invention may be applied to other image forming apparatuses such as a copying machine and a multifunction machine.

DESCRIPTION OF SYMBOLS 1 Laser printer 2 Apparatus main body 3 Discharge unit 7 Image formation part 16 1st discharge tray 51 1st wall 51A Upper end part 52 2nd wall 53 Flapper 53A 1st curved surface 61 2nd discharge tray 62A 3rd curved surface 66 3rd wall 67 4th wall 67A 2nd curved surface 100 Curl amount adjusting mechanism 111 Curling part 120 Receiving part 200 Control part P Branch point S Paper

Claims (12)

An apparatus main body having an image forming unit and a first discharge tray, and a discharge unit having a second discharge tray attached to the upper part;
A first discharge unit that guides the sheet carried out from the image forming unit to the first discharge tray;
A second discharge portion that branches from the first discharge portion, extends upward from a branch point with the first discharge portion, and guides the sheet to the second discharge tray;
A curling portion for curling the sheet so that the sheet is curved in the cross section in the width direction,
The image forming apparatus, wherein the curling unit adds a curl to a sheet conveyed to the second discharge unit. The first discharge portion has a first bending portion that curves away from the second discharge portion from the branch point toward the downstream side from the upstream side in the sheet conveyance direction,
The image forming apparatus according to claim 1, wherein a curl amount of the sheet conveyed to the second discharge unit is larger than a curl amount of the sheet conveyed to the first discharge unit. The curling unit has a receiving unit that is disposed on the opposite side of the curling unit with the sheet to be conveyed interposed therebetween and receives the conveyed sheet, and the curling unit has a predetermined distance from the receiving unit. The curl amount of the conveyed sheet can be adjusted by advancing and retracting to a first position that is a position that is spaced apart and a second position that is closer to the receiving part than the first position. It has a curl amount adjustment mechanism,
3. The image forming apparatus according to claim 2, wherein the curl amount adjusting mechanism is disposed between a branch point between the first discharge unit and the second discharge unit and the image forming unit. . A flapper movable between a first discharge position for guiding the sheet to the first discharge tray and a second discharge position for guiding the sheet to the second discharge tray;
The curling portion moves forward and backward in conjunction with the flapper, and is disposed at the first position when the flapper moves to the first discharge position, and when the flapper moves to the second discharge position, The image forming apparatus according to claim 3, wherein the image forming apparatus is disposed at a second position.   5. The image forming apparatus according to claim 3, wherein the curling unit is inclined so as to approach the receiving unit from an upstream side to a downstream side in a sheet conveyance direction. The discharge unit includes a third discharge unit that guides a sheet that has passed through the second discharge unit upward, and a fourth discharge unit that branches from the third discharge unit and guides the sheet to the second discharge tray. Have
The fourth discharge portion is bent away from an extension line of the third discharge portion from the branch point with the third discharge portion toward the downstream side in the sheet conveyance direction, and the first bend. The image forming apparatus according to claim 3, further comprising a second curved portion having a larger radius of curvature than the portion.   The image forming apparatus according to claim 3, wherein the first position is a position outside a path along which the sheet is conveyed. A control unit for controlling the curl adjustment mechanism;
The discharge unit includes a third discharge unit that guides a sheet that has passed through the second discharge unit upward, and a fourth discharge unit that branches from the third discharge unit and guides the sheet to the second discharge tray. Have
A plurality of the second discharge trays are provided side by side in the direction in which the third discharge portion extends,
When the sheet is discharged to each second discharge tray, the control unit is arranged downstream of the third discharge unit based on a curl amount of the sheet discharged to the second discharge tray disposed on the upstream side of the third discharge unit. The image forming apparatus according to claim 3, wherein a curl amount of a sheet discharged to a second discharge tray disposed on the side is increased. A control unit for controlling the curl adjustment mechanism;
9. The control unit according to claim 3, wherein the control unit reduces a curl amount in the case of a sheet thicker than a predetermined thickness than in the case of the sheet having the predetermined thickness. Image forming apparatus. A control unit for controlling the curl adjustment mechanism;
10. The control unit according to claim 3, wherein the control unit increases a curl amount in the case of a sheet thinner than a predetermined thickness than in the case of the sheet having the predetermined thickness. Image forming apparatus.   The image forming apparatus according to claim 2, wherein the curling unit is disposed in the second discharge unit. The discharge unit has a plurality of conveying rollers arranged in the width direction of the sheet,
12. The image forming apparatus according to claim 1, wherein the plurality of conveying rollers are arranged at positions different from a portion where the curl amount of the sheet is maximized.

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